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Accueil du site → Doctorat → Allemagne → 2012 → Impact of Soil Amended Superabsorbent Polymers on the Efficiency of Irrigation Measures in Jordanian Agriculture

Technischen Universität Carolo-Wilhelmina zu Braunschweig (2012)

Impact of Soil Amended Superabsorbent Polymers on the Efficiency of Irrigation Measures in Jordanian Agriculture

Altarawneh, Amjad Asri Abed

Titre : Impact of Soil Amended Superabsorbent Polymers on the Efficiency of Irrigation Measures in Jordanian Agriculture

Auteur : Altarawneh, Amjad Asri Abed

Université de soutenance : Technischen Universität Carolo-Wilhelmina zu Braunschweig

Grade : Doktors der Naturwissenschaften (Dr.rer.nat) 2012

Résumé
Since several years, studies have been initiated on how far the application of superabsorbent polymers can contribute to optimize irrigation measures by enhancing the water availability for plants. Therefore, the scope of the present study was to investigate the impact of the potassium-polyacrylates polymer (SAP) application on the irrigation efficiency for eggplant cultivation. The SAP were applied at 0, 0.2 and 0.4% to sandy soil. Irrigation was performed using fresh water, treated wastewater and artificial wastewaters. Heavy metals as well as bacteria were analyzed in irrigation waters, soil and eggplants. During the vegetation period, growth parameters of the eggplants were determined. In additional pot and laboratory tests, the role of the SAP on the water availability and on the sorption of cadmium in soil was studied. The highest eggplant growth rate, biomass and fruit yields as well as the enhancement of available water were achieved at 0.2% SAP. The high soil alkalinity triggered the metal precipitation at the superficial soil layer and prevents metal entry into the rhizosphere and finally plant uptake. Total organic carbon, total nitrogen, soil respiration and soil pH were not affected by the SAP concentration. The electric conductivity increased with the increasing SAP concentration. The total bacterial counts in soil decreased with increasing of SAP concentration. SAP showed a high affinity to irreversibly sorb metals like Cd. The increase of the eggplant yield did not compensate the costs for the SAP application. The only economic benefit found in 0.2% amendment irrigated with salty water. In additional tests, endophytic bacteria were not found in any eggplant parts. The SAP was not degradable by the local bacterial isolates (K. pneumoniae, C. diphtheriae and B. subtilis). The cadmium-resistant bacterial isolates (B. subtilis and K. pneumoniae) were able to accumulate 30-50% of cadmium compared with the amount sorbed by soil amended with 0.4% SAP.

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